ASoC: WM9081 interrupt status register is volatile

Not that we have interrupt handling in the driver at the minute.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

sound/soc/codecs/wm9081.c

@@ -173,6 +173,7 @@ static int wm9081_volatile_register(struct snd_soc_codec *codec, unsigned int re
 {
 	switch (reg) {
 	case WM9081_SOFTWARE_RESET:
+	case WM9081_INTERRUPT_STATUS:
 		return 1;
 	default:
 		return 0;